Commutator for dynamos and electric motors



r 2 Sheets-Sheet 1, H. GROSWITH & R. ASHLEY. GOMMUTATOR FOR DYNAMOS AND ELECTRIC MOTORS.

Patented Jan. 3

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aim-52k 2 2 Sheets- ShGet 2. H. GROSWITH & R. ASHLEY. GOMMUTATOR FOR DYNAMOS AND ELECTRIC MOTORS.

(No Model.)-

Paten'ted Jan 3 Jam" UNITED STATES PATENT OFFICE.

ASSIGNORS, BY MESNE ASSIGNMENTS, TO THE UNITED TRIG COMPANY, OF NEW JERSEY.

COLUMBIAN ELEC- COMMUTATOR FOR DYNAMOS AND ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 489,000, dated January 3, 1893. Application filed February 18, 1892. Serial No. 421,920. (No model.)

To whom it may concern.-

Be it known that we, HENRY Gnoswrrrrand RALPH ASHLEY, citizens of the United States,

and residents of Philadelphia, in the county of Philadelphia and State of Pennsylvania,

have invented certain new and useful Improvements in Oommutators for Dynamos and Electric Motors; and we do hereby declare that the following is afull, clear, and exact description of theinvention, which will enable others skilled in the art to-which itapper- .tains to make and use the same, reference being bad to the accompanying drawings, which form a part of this specification, and in which I Figure l is aperspective view of the armature of an electric-motor equipped with our improved commutator; Fig. 2 is a front or face view of our improved disk commutator; Fig. 3 is a rear view of the same, showing the iron hub, frame, and its reinforcing-spokes or ribs; and Fig. 4 is a sectional view on the broken line marked w sc in Figs. 2 and 3.

Like letters of reference denote cor-responding parts in all the figures.

Our invention relates to commutators, for dynanios or electric motors, of the type known as disk commutators; that is to say, commutators in the nature of a flat circular disk affixed to the end (or ends) of the armature at right angles to the shaft thereof, so as to revolve in avertical plane; the face of the disk comprising a series of metallic sectors separated from oa'ieuanother by insulating material and adapted to be placed in frictional contact with the brushes. In commutators of this type, it is desirable to so construct the sectors, which form the brush-contacts, ,that any one or all of them may be 40 easily removedfrom their hearing or seat on the armature; that-they shall present, at all times, a perfectly smooth and plane surface to the brushes, so as to avoid sparking and undue friction (involving both loss of power and undue waste of brush material); and so that the weight of the commutator (or cominutators) shall be reduced to a minimum.

With these several objects in view, our invention consists in the improved construction and combination of parts of a disk. commutator as will be hereinafter more fully described aud claimed.

Referring to the accompanying two sheets of drawings, the letterA designates an electric motor of any approved type, the armature B of which is provided with disk conimutors, one of which is shown at O. This commutator comprises an iron hub D, cast in one piece with a flat circular disk E; a se ries of brass sectors or contact-plates F; and a steel clamping-ring G. i r

In order to give the proper strength and rigidity to the cast-iron disk E without making it too heavy, the flat back of this disk is cast with reinforcing-ribs or webs, H, extending radially from the hub D to the flanged 'ri n1 1. The hub itself is bored through around its central aperture for the insertion of bolts or screws J, whereby it is firmly fastened to the adjacent end of the armature core (not shown).

The face of disk E is cut out around the hub so as to form an undercut or V- shaped annular recess, K, encircling the hub on its front side, and the flanged rim 1 is screw-threaded to receive an interiorly threaded steel ring or annulus G, the overlapping front side of which is also undercut to form a V-shaped recess K, corresponding to the undercut recess, K, around the hub.

The contact-plates F,of brass or othersuitable metal, are in the nature of sectors, truncated at their inner ends where they abut against the undercut rim of the hub. Each of these plates has top and bottom projections, 8 f and f,of such sizeandshapethattheywill fit, respectively, into the V-shaped undercut recesses K and K as shown in Fig. 4. Apacking, L, of vulcanized fiber, rubber, or other suitable insulating material, is placed within the seat formed in the face of disk E in conjunction with ring G, for the two-fold purpose of securing complete insulation between the contact-plates and the hub, disk and ring, which, together, form the seat or bearings of' 5 said plates, and also provide a firm seat for the plates by the elasticity of the packing, which is compressed by the screwing home of the clamping-ring, G, wherebythe plates are firmly clamped in their seat adjacent to one another. Strips of this insulated paeking are also placed between the contact plates F, as shown at L in Fig. 2, for the purpose of separating and insulating said plates from one another. hen the plates have all been properly inserted into their seat in the castiron disk and firmly fastened therein by placing in position over the rim, and screwing home, the clamping-ring G, the projecting faces of the plates which overlap both the ring and the hub are planed off and ground with emery so as to present a perfectly smooth and plane surface to the brushes, after which the commutator is ready to be bolted to the armature and have its sectors F connected electrically with the wires of the armature windings or bobbins.

This connection maybe made in any of the various well-known ways; but we prefer to use an improved connection, which ofiers many advantages, but whieh-as it may be used advantageously with armatures and co mmutators of many different constructions, and is not confined or limited for use with our improved commutator--will *form the subject of a separate application of even date herewith Serial No. $21,928.

It will be observed that we dispense entirely with the use of screws or other fastenings for attaching the commutator sectors to their backings, so that there are no projecting screw-heads, or eountersinks, to mar the smoothness of the disk and cause sparking, and it will furtherbe seen that by simply unscrewing the annulus or clampingring G and removing it from the disk, any one of the sectors maybe removed or replaced at will without disturbing the rest. Owing to the interposition of the insulated packing L between the sectors or contact-plates F and the disk E and ring G, there is also a certain amount of elasticity which operates beneficially in conjunction with the pressure of the brushes against the smooth face of the commutator.

Having thus described our invention, we claim and desire to secure by Letters Patent of the United States:

esaoco 1. A disk commutator comprising, in combination, a circular disk or backing-plate having an undercut hub and screw-threaded rim; a screw-threaded clamping-ring having an undercut projecting annulus; a series of sectors or contact-plates having projections titting into the recesses formed by the undercut hub and undercut annulus; and insulating packing separating the sectors and their projections from their seat in the disk and from one another, substantially as and for thepurpose set forth.

2. In disk eommutators, the circular disk or backing-plate having an undercut projecting hub bored through around its central aperture to receive bolts for its attachment to the armature core, and provided with ascrewthreaded flanged rim and radial reinforcingribs, substantially as and for the purpose set forth.

3. The combination, in disk commutator-s, with the backing-plate having a projecting hub undercut with a Vshaped groove or recess and a screw-threaded flanged rim, of the interiorly threaded clamping-ring having a projecting undercut annulus overlapping the circular rim of the disk and adapted to clamp the contact-plates-or sectors against an insulated packing interposed between said sectors, the face of the backing-disk, and the undercut annulus, substantially as and for the purpose set forth.

4. In disk commutators, the sector-shaped contact-plates having V-shaped projections at top and bottom, in combination with the circular screw-threaded and undercut backing-disk and threaded annulus or clampingring; substantially as and for the purpose set forth. I

In testimony that we claim the foregoing as our own we have hereunto affixed our signatures in presence of two witnesses.

HENRY GROSWITH. RALPH ASHLEY.

Witnesses:

THEO. II. MCCALLA, C. W. KENNEDY. 

